1. Field of the Invention
The present invention relates to processes and assemblies for identifying and tracking assets, such as tubulars, equipment and tools used in subterranean wells, and more particularly, to processes and assemblies for identifying and tracking such assets which facilitates accurate input of data into a data base.
2. Description of Related Art
Tubulars are commonly employed in subterranean wells. During drilling of a subterranean well bore, a drill bit is secured to one end of a drill string which is made up of individual lengths of drill pipe. These lengths are conventionally secured together by means of a threaded collar. After the drill bit is secured to a first length of drill pipe, the bit and first length of drill pipe are lowered to the ground and usually rotated to permit the bit to penetrate the earth. Drilling fluid is circulated via the interior of the pipe to the drill bit to lubricate the bit and to carry cuttings back to the drilling rig at the surface of the earth via the annulus formed between the bore hole being drilled and the drill pipe. As drilling progresses, additional lengths of drill pipe are secured to the uppermost length of drill pipe in the well bore. As this process continues, a drill string is formed that is made up of individual lengths of drill pipe secured together. Once the well bore is drilled to the desired depth, the well bore is completed by positioning a casing string within the well bore to increase the integrity thereof and provide a path for producing fluids to the surface. The casing string is normally made up of individual lengths of relatively large diameter metal tubulars which are secured together by any suitable means, for example screw threads or welds. Usually, each length of casing is provided with male screw threads at each end thereof and individual lengths of casing are joined together by means of a collar having female screw threads at each end thereof. Conventionally, after the casing string is cemented to the well bore face and perforated to establish fluid communication between the subterranean formation and the interior of the casing string, a production tubing string is positioned within the casing string to convey fluids produced into the well to the surface of the earth. Tubing strings are conventionally made up of individual lengths of relatively small diameter tubing secured together by collars in a manner as described above with respect to casing. Tubing strings may also be used to convey fluids to treat the well or a subterranean formation of interest or to convey tools or equipment, such as packers, plugs, etc., that are needed to complete or work over a well.
Tubulars are transported to the well site in anticipation of an operation and are temporarily stored there until deployed into a well. At the well site, each length of tubular is measured or tagged to determine the exact length thereof. Because each tubular as manufactured usually varies in length, it is important to determine and know the exact length thereof so that the total length of a given tubular string that is positioned in a subterranean well is known. As the first tubular of a given string is positioned in a well, the tubular is designated with a first number, e.g. 1, and the length thereof is manually recorded at the well site into either a paper or computer data base. As each subsequent individual length of tubular is secured to the tubular string already positioned in the well, the next consecutive number that is assigned to that tubular and its exact length is also manually recorded into the data base at the well site. In this manner, the exact number of tubulars that make up a given string positioned in a subterranean well and the exact length of the string is known. The compilation of a data base in this manner is also desirable so as to maintain an accurate history of the usage of tubulars, equipment and/or tools. Such history of usage can be used to provide maintenance and predict potential problems. However, problems routinely occur with this procedure due to manual error(s) in entering into the data base tubular length(s) that are not part of the tubular string positioned in a well, in entering the wrong sequence of individual tubular lengths that make up a string, and/or in failing to enter an individual tubular length(s) that is part of a tubular string positioned in a subterranean well. Such errors lead to time consuming problem solving, while expensive rigs are often present at the well site, to determine the precise depth of the well, of a certain individual length of casing, and/or of a certain downhole tool. Further problems occur with this conventional method when tubulars are withdrawn from the well bore, temporarily stored on site and subsequently used in a different operation at that well or transported and used in a different well. In accordance with this conventional method, individual lengths of tubulars removed from a well are stacked at the well site without any consideration given to the number assigned to that tubular as run into the well. The individual length of tubulars are not actually physically marked with a designation number and marking such tubulars as they are being pulled from a well is not practical since the rig necessary for performing this operation is expensive. In some instances, individual lengths of drill pipe are provided with a unique serial number from the manufacturer which is entered into the data base as the drill string is being made up. However, such entry is expensive and plagued by manual errors, and often, the serial number of an individual length of drill pipe is not easily found or illegible if found due to rust, corrosion, wear, etc.
In an effort to automate the data input process and to provide a completely accurate information data base, a system has been developed to track asset inventory wherein an electronic tag, such as a passive radio frequency chip, is attached to articles of manufacture that are used in the oil & gas industry. A hand held wand is employed by field personnel to read such electronic tag and the code gleaned during such reading is transferred by cable to a hand held portable terminal. This information is then sent to a personal computer. This system is commercially available from Den-Con Tool Company of Oklahoma City, Okla. under the trade name designation Print System. However, electronic tags, such as a passive radio frequency chip, do not transmit through steel, and therefor, require field personnel to position the hand held wand adjacent and close to the tag to read it. Thus, the use of this system at field locations, such as drilling and completion rigs, offshore platforms etc., has proved to be inefficient since field personnel must first locate the position of the electronic tag and then properly position the wand in extremely close proximity to the tag, sometimes repeating the procedure to ensure that the tag is properly read. This is time consuming and expensive.
Thus, a need exists for an identification and tracking method wherein individual lengths of tubulars, pieces of equipment or tools are accurately identified and inventoried prior to deployment in a given subterranean well, as positioned in a well and/or as stacked at a well site after being pulled from a well and awaiting deployment in the same or different wells. A further need exists for effectively eliminating errors in data base entry for information about individual lengths of tubulars, equipment and/or tools. A still further need exists for eliminating time delays associated with automated reading of radio frequency identification devices employed to identify and track tubulars or other tools or equipment.